The bigoted attack on the judge's heritage was hardly surprising since white nationalism is part of his appeal. His vitriol also elicited condemnation for his flagrant disregard for judicial independence and the rule of law.

Yet, the Republican party is largely circling the wagons, privileging party loyalty and reclaiming the White House over principled resistance to the pernicious politics of hatred and exclusion and the authoritarianism Trump's demagoguery threatens to usher in.

Inflammatory rhetoric

Trump said that federal Judge Gonzalo Curiel, a respected jurist who was born in the United States, had an "inherent conflict of interest", and issued unfair rulings because of his Mexican heritage, owing to the nominee's plan to build a wall on the US-Mexico border and his immigration policies.

Facing an outcry, Trump was unrepentant, initially doubling down instead and suggesting Muslims could also be unqualified to preside over a case against him because of his proposed temporary ban on Muslims entering the country.

Having shed the patina of respectable deniability, Trump finally crossed a line, eliciting push back from that party that had been impervious to his inflammatory rhetoric.

Yet, Trump's Republican support remains largely intact: Only a handful of legislators distanced themselves from the candidate. Others, like House Speaker Paul Ryan, denounced the remark as "the textbook definition of a racist comment", but vowed ongoing support. A few even rallied to Trump's defence, denying the comments were offensive.

Bowing to mounting pressure, Trump later toned down his accusation, arguing that his comments had been misconstrued, but notably declining to apologise. He was clearly not chastened by the rebukes, continuing to call Democratic Senator Elizabeth Warren "Pocahontas", to denigrate her claimed Native American heritage.

Nothing new

The incendiary rhetoric is nothing new: Trump's campaign has been predicated on bigotry since its inception.

He built his platform on white nativism, launching into an attack on Mexican migrants just minutes into his speech announcing his candidacy, but opportunistically stoking resentment predates Trump's candidacy.

In the aftermath of the horrific Orlando massacre and the escalating importance of tolerance and unity, GOP leaders should muster the integrity and courage to reign in Trump's dangerous demagoguery.

In 2013, when questioned about his support for "birtherism" - a xenophobic campaign to discredit President Barack Obama's legitimacy by questioning his birthplace, Trump said"I don't think I went overboard. Actually, I think it made me very popular ... I do think I know what I'm doing."

Exploitation of white disaffection

Ronald Reagan dog-whistled about states' rights to mask opposition to federally mandated equality at a speech in Philadelphia, Mississippi, not far from where three civil rights workers were gunned down in 1964, and employed the disparaging, racially coded imagery of "welfare queens".

Supporters of Trump point and scream at an anti-Trump demonstrator holding a sign during a Trump campaign rally in Fountain Hills, Arizona. [Reuters]

Similarly, Trump has deftly exploited the disaffection of white voters already beleaguered by the erosion of financial stability, the projected diminution of the white majority and the insecurity that demographic change engenders, and the unfolding backlash against a black president.

Unsurprisingly, Trump's comments about Curiel elicited a partisan response: according to a recent poll, only 22 percent of Republicans believed the comments were racist. In contrast, 81 percent of Democrats and 44 percent of independents believed they were.

The resentments stoked by Trump's invective will not be easy to extinguish, and the damage is already evident.

Aside from an even more bitterly polarised electorate, the inflammatory rhetoric is exacting a harrowing toll on minority children.

In one study by the Southern Poverty Law Center, 67 percent of teachers reported alarming levels of anxiety, that "students of colour are worried about what will happen to them under a Trump presidency," and an increase in racially motivated bullying.

Nativist hostility

Trump's disregard for principles of democratic accountability and the rule of law should also sound alarm bells.

Federal judges are not required to recuse themselves based solely on race or ethnicity. They are bound to carry out their duties impartially, and there is no evidence Curiel has failed to do so here.

In fact, his rulings appear quite even-handed. If Trump's attorneys had any real evidence of biased rulings, they could seek his recusal. Their failure to do so suggests that he is improperly trying to influence the outcome of the case or divert attention from evidence he defrauded vulnerable students.

The self-serving accusations bode poorly for Trump's future respect for the independence of a judiciary that will inevitably be called on to rule on questions of constitutional import.

Especially in the aftermath of the horrific Orlando massacre and the escalating importance of tolerance and unity, Republican leaders should muster the integrity and courage to reign in Trump's dangerous demagoguery.

Though the racialised and nativist hostility he has exploited will not evaporate with Trump's defeat, it would be immeasurably amplified if he wins.

Either way, the enduring damage to the country's international standing and founding ideals is already incalculable.

Lauren Carasik is a clinical professor of law and the Director of the International Human Rights Clinic at Western New England University School of Law.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.